Osteosarcoma, a malignant bone tumor, occurs most commonly in the second and third decades of life. Treatment of localized disease with amputation alone has historically resulted in a long-term survival of approximately 20%, although over the past ten years there appears to have been an increase in survival rates such that figures of 40 to 50% five year survival are now being projected. Although several chemotherapy agents have been found to cause tumor stabilization or regression in patients with metastatic disease, the benefit of these drugs in the adjuvant setting, ie., after surgical removal of a localized tumor, is much debated. The purpose of this study, which is being conducted in a multi-institutional setting, is to evaluate the efficacy of adjuvant chemotherapy, using all the currently known "first line" drugs with activity against osteosarcoma, in children with localized tumor of the extremity who have been rendered disease-free by amputation or a limb-salvage procedure. The patients are randomly assigned to receive either immediate adjuvant chemotherapy using bleomycin/actinomycin D/cyclophosphamide, high dose methotrexate, adriamycin and cisplatinum for 43 weeks (regimen 1) or to receive no immediate chemotherapy (regimen 2). Those patients on regimen 2 who subsequently experienced tumor relapse then receive the chemotherapy schema given to regimen 1 patients after surgical resection of as much recurrent tumor as possible. The study was opened in May 1982 and results thus far are too early for detailed evaluation, although to date there is no significant difference between the relapse rate in the two arms. Although morbidity has been significant, no treatment-related mortality has thus far been reported.